[Shader Graph Gen.] Introduce QShaderGraphLoader

This class allows to load a shader graph from its JSON representation.
To avoid duplicating the shader snippets inside of the JSON which would
be a maintenance nightmare, we instead allow to register a set of node
prototypes by their name and only refer to said names inside the JSON.

Change-Id: I3e7b39e8b3c25f51f331a0a59dda883ac8e2bc57
Reviewed-by: Sean Harmer <sean.harmer@kdab.com>

1 files changed, 99 insertions, 0 deletions

diff --git a/src/gui/util/qshadergraphloader_p.h b/src/gui/util/qshadergraphloader_p.h
new file mode 100644
index 0000000000..97cbd8d18c
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+++ b/src/gui/util/qshadergraphloader_p.h
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+/****************************************************************************
+**
+** Copyright (C) 2017 Klaralvdalens Datakonsult AB (KDAB).
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the QtGui module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or (at your option) the GNU General
+** Public license version 3 or any later version approved by the KDE Free
+** Qt Foundation. The licenses are as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-2.0.html and
+** https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef QSHADERGRAPHLOADER_P_H
+#define QSHADERGRAPHLOADER_P_H
+
+//
+//  W A R N I N G
+//  -------------
+//
+// This file is not part of the Qt API.  It exists purely as an
+// implementation detail.  This header file may change from version to
+// version without notice, or even be removed.
+//
+// We mean it.
+//
+
+#include <QtGui/private/qtguiglobal_p.h>
+
+#include <QtGui/private/qshadergraph_p.h>
+
+QT_BEGIN_NAMESPACE
+
+class QIODevice;
+
+class QShaderGraphLoader
+{
+public:
+    enum Status : char {
+        Null,
+        Waiting,
+        Ready,
+        Error
+    };
+
+    Q_GUI_EXPORT QShaderGraphLoader() Q_DECL_NOTHROW;
+
+    Q_GUI_EXPORT Status status() const Q_DECL_NOTHROW;
+    Q_GUI_EXPORT QShaderGraph graph() const Q_DECL_NOTHROW;
+
+    Q_GUI_EXPORT QIODevice *device() const Q_DECL_NOTHROW;
+    Q_GUI_EXPORT void setDevice(QIODevice *device) Q_DECL_NOTHROW;
+
+    Q_GUI_EXPORT QHash<QString, QShaderNode> prototypes() const Q_DECL_NOTHROW;
+    Q_GUI_EXPORT void setPrototypes(const QHash<QString, QShaderNode> &prototypes) Q_DECL_NOTHROW;
+
+    Q_GUI_EXPORT void load();
+
+private:
+    Status m_status;
+    QIODevice *m_device;
+    QHash<QString, QShaderNode> m_prototypes;
+    QShaderGraph m_graph;
+};
+
+Q_DECLARE_TYPEINFO(QShaderGraphLoader, Q_MOVABLE_TYPE);
+
+QT_END_NAMESPACE
+
+Q_DECLARE_METATYPE(QShaderGraphLoader)
+Q_DECLARE_METATYPE(QShaderGraphLoader::Status)
+
+#endif // QSHADERGRAPHLOADER_P_H